The "LS Swap" Shouldn't Be Limited to the Aftermarket

It's a road I've driven for most of my life, an empty rural highway with plenty of twists and the occasional grade change. Neither a true freeway slab nor an old-school two-lane state route. For a long part of my youth, there was no gas station on the road for nearly forty miles, so I tended to watch my fuel consumption when I was driving it.

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My old five-point-oh-Ford-powered Mercury Marquis coupe returned about eight MPG on that route, way back in '89. But I expected that a "V8 gas guzzler" would be thirsty, particularly since the Variable Venturi carburetor sitting on the intake was a Rube Goldberg nightmare of vacuum leaks and unexpected 60-mph stalls. Nor could my friends in their old A-body GM cars and 318-equipped Dodge Diplomats really do any better. If you got twelve miles per gallon, it was because you had enough tailwind to push the Tirpitz out of harbor.

As the years came and went, I found myself driving a variety of much nicer cars on that same road, many of which had eight cylinders under the hood. They were all quite a bit more efficient than that Marquis Brougham of mine, but none of them would exactly make an accountant smile. The worst of them: a CL55 AMG that never returned more than 14 MPG no matter what I did. The best: my 2009 Lincoln Town Car, which could average just a touch over 22. In the middle, a rogue's gallery of Audis, Mercedes-Benzes, VW Phaetons, and one Caprice Classic "bubble wagon." All stuck between 15 and 21 miles per gallon.

So you can imagine my surprise when I looked down yesterday and saw "23.2" on the fuel-economy readout of the V8-equipped vehicle I was driving. No heavy tailwind, no tractor-trailer to draft. Here's something even more surprising: the V8 in question was a 6.2-liter, 420-horsepower monster that sounded uncannily like it might have provided the studio track for Days Of Thunder. And here's the biggest shock of all: I was driving a crew-cab pickup truck. A crew-cab four-by-four pickup truck. With a 12,000-pound tow package.

Surely there was some kind of mistake on the part of the trip computer. So I ran the truck a full four hundred and thirty miles before filling it up. Over hill and dale, up and down the steep grades of the West Virginia Turnpike. I didn't drive aggressively but neither did I spare those 420 horses when I needed them. The trip computer settled on an average of 21.8mpg, on the same route that my V8-powered, six-speed manual Audi S5 would return eighteen. Finally, at the Exxon near Hillsville, North Carolina, I stopped to fill up.

Nineteen point six gallons. Guess the trip computer was right after all. Call the local bishop—we've got a bona fide miracle on our hands.

Or so you'd think, anyway. But when you hear the hoofbeats of admirable efficiency, it's best to think of the horses of careful, iterative efficiency instead of those zebras with their 100-MPG carburetors. General Motors has damn near perfected the "small block Chevy" over the past twenty years. It doesn't really matter what task you give the SBC-LS-LT family of engines. In a Corvette Grand Sport, it's a rip-roaring wayback machine. In a Tahoe, it's a silent servant. And here in the crew-cab tow rig, it's an odd combination of hooligan and tireless laborer.

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One of my Instagram followers said that the truck was "quicker, and more efficient, than a Nissan 350Z from just a few years ago." He forgot to mention that you can tow a 350Z behind a Silverado, but doing the reverse is a recipe for reaching the front page of your local newspaper. My first thought upon reading his comment was "man, this engine would be brilliant in an old 350Z".

Obviously, I'm far from the first person to think of that. So many Z-cars have received GM V8s that there are multiple installation kits available. The same is true for the Miata. And the Porsche 944. And just about anything else out there you might imagine. Hell, I've even seen them in Cobra replicas, which is all sorts of wrong from a historical perspective but all sorts of right when you're driving the car in question.

The whole world knows that the "LS swap" is a ticket to a nearly unbeatable combination of economy, power, performance, and durability. So why doesn't GM itself seem to know that? They used to know it. I'm not even talking about the Seventies, when the addition of a 350 made the Chevy Monza or Malibu a tolerable proposition. As recently as eight years ago, you could get an LS V8 in automobiles as diverse as the CTS-V and the Impala SS. RWD, FWD, it didn't seem to make a difference. If memory serves, there was even briefly a Grand Prix that had wider front tires to handle the V8 power.

The aforementioned Pontiac.

Pontiac

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Now here we are, in 2017, and it's a golden era of GM platform engineering. The ATS has a sublime chassis. The top-of-the-line Cadillac sedan is RWD for the first time in more than two decades. And they've got the V8s to the point where they return stellar economy numbers in massive trucks. So why not slap them into everything from the Malibu on up, at least as an option? With the sole exception of the soon-to-disappear SS, looking at GM's showrooms would make you think that it was illegal to offer a choice like that.

Imagine being able to buy a new Malibu with a 400-horsepower V8 turning all four wheels and returning nearly thirty MPG. Or hearing that new CT6 rolling by with a 6.2-liter "small-block" under the hood? And here's the best part: the General's competitors have no easy answer to it. Everybody else got rid of their compact, lightweight OHV engines decades ago. Try putting a Ford "Voodoo" in a Fusion, why dontcha? Or the old 40-valve engine that powered my first-gen Audi S8—into a new Audi S3? You're gonna need a bigger crowbar, friendo.

If that's too risky, too wacky, too brave of an idea, for the modern GM management to consider, maybe they'd be willing to put the engine from the Silverado directly into the ATS-V, just the way it is? I know, I know—the twin-turbo V6 is there because the competition has twin-turbo V6es and nobody wants to think of the ATS-V as a Cadillac Camaro. But as my mother used to say to me: "If everybody else jumped off the Brooklyn Bridge, would you do it?" GM doesn't need to jump off the crappy turbo-motor bridge.

It's time to V8 all the things. The good news is that if GM won't do it, the aftermarket eventually will. They just won't do it with a warranty, or dealership support, or 72-month financing. Which means that a lot of people will never have the chance to experience what these great engines can truly do. Unless they're willing to do what a massive number of American car buyers are doing nowadays: get a truck instead. I admit, it's a hell of a thrill to skip gas stations in a crew-cab with a NASCAR soundtrack. I'd just rather do it in a nice, old-fashioned car.

Born in Brooklyn but banished to Ohio, Jack Baruth has won races on four different kinds of bicycles and in seven different kinds of cars. Everything he writes should probably come with a trigger warning. His column, Avoidable Contact, runs twice a week.

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